Image inspection device and image inspection method

Abstract

Provided are an image inspection device and an image inspection method capable of determining an actual image-capturing angle with respect to a workpiece. An image inspection device (1) is characterized by comprising: a mirror rotating body (12); an image-capturing unit (13); a positioning reference alignment unit that is provided to the mirror rotating body (12) so as to rotate integrally with the mirror rotating body (12) to be image-captured together with a workpiece; a drive unit (14) that drives rotation of the mirror rotating body (12); an image-capturing processing unit (151) that causes the drive unit (14) to drive the rotation of the mirror rotating body (12), and causes the image-capturing unit (13) to capture an image of the workpiece upon positioning of the mirror rotating body (12) at a preset setting angle; and an image-capturing angle acquisition unit (152) that acquires an actual image-capturing angle of a captured image corresponding to the setting angle on the basis of the alignment unit appearing in the captured image.

Description

Image inspection device and image inspection method

[0001] The present invention relates to an image inspection device and an image inspection method for photographing a workpiece and performing inspection using the photographed image.

[0002] Conventionally, an image inspection device and an image inspection method for photographing and inspecting a workpiece are known (see, for example, Patent Document 1). In the image inspection device and image inspection method described in Patent Document 1, the workpiece is photographed by guiding subject light to an imaging unit using an annular mirror arranged around the workpiece. In the technology described in Patent Document 1, the workpiece is photographed as a single image around the central axis of the mirror.

[0003] In response to this, there is a demand for inspecting the appearance of a workpiece individually from one or more directions, and so technologies that enable photographing of the workpiece from any direction have been considered. One example of such a technology is a technology in which a mirror rotating body that can rotate around the workpiece guides subject light to an imaging unit, thereby photographing the workpiece from a direction according to the position of the mirror rotating body.

[0004] Japanese Patent Application Laid-Open No. 2003-240728

[0005] Here, in the above-mentioned technology, the set angle on the drive side of the mirror rotor is used as the imaging angle for the workpiece, but the actual imaging angle may include an inclination angle due to the structure of the mirror rotor, etc., and it is currently difficult to grasp this. For this reason, it is difficult to evaluate whether the inclination of the workpiece shown in a certain captured image is due to the imaging angle or the inclination of the workpiece itself, and there is a demand for technology that can determine the actual imaging angle.

[0006] Therefore, the present invention focuses on the above-mentioned problems and aims to provide an image inspection device and an image inspection method that can determine the actual shooting angle for a workpiece.

[0007] In order to solve the above problem, the image inspection device is characterized by comprising: a mirror rotor having one or more mirrors rotatable around a predetermined axis, which reflects subject light from a workpiece placed as an inspection target on the axis and guides it to a shooting position; a shooting unit which is installed at the shooting position and receives the subject light to photograph the workpiece; an alignment unit which is installed on the mirror rotor so as to rotate together with the mirror rotor around the axis and be photographed together with the workpiece, and which serves as a reference for positioning the workpiece; a drive unit which drives the mirror rotor to rotate around the axis; an imaging processing unit which drives the drive unit to rotate the mirror rotor and causes the imaging unit to photograph the workpiece when the mirror rotor is positioned at a predetermined set angle; and an imaging angle acquisition unit which acquires the actual shooting angle of the captured image corresponding to the set angle based on the alignment unit which appears in the captured image.

[0008] In addition, in order to solve the above problem, the image inspection method is characterized by comprising a work placement process for placing the work on the axis of the above-mentioned image inspection device, a photographing process process for driving the mirror rotor to rotate with the drive unit and causing the photographing unit to photograph the work when the mirror rotor is positioned at a predetermined setting angle, and a photographing angle acquisition process for acquiring the actual photographing angle of the photographed image corresponding to the setting angle based on the alignment unit that appears in the photographed image.

[0009] According to the image inspection device and image inspection method described above, the actual imaging angle can be determined.

[0010] 1 is a perspective view showing an image inspection device according to an embodiment; FIG. 1 is a perspective view of the mirror rotor shown in FIG. 1 as seen from the workpiece side; FIG. 2 is a plan view showing the state of the mirror rotor shown in FIG. 2 rotated around an axis serving as the center of rotation, as viewed from the direction of arrow V11 in FIG. 2; FIG. 3 is a cross-sectional view taken along line V12-V12 in FIG. 2 showing how subject light from the workpiece is directed toward the imaging unit in the mirror rotor shown in FIG. 2; FIG. 4 is a schematic view showing an arrangement of images captured at four set angles from 0° to 135°; FIG. 5 is a schematic view showing an arrangement of images captured at four set angles from 180° to 315°; FIG. 6 is a diagram showing an alignment unit used to obtain the actual imaging angle; FIG. 7 is a diagram showing how the mirror rotor is set to an initial setting angle of 0° for calculating angular deviation in the image inspection device shown in FIG. 1; FIG. 8 is a schematic view showing how the angular deviation from the initial setting angle is calculated based on an initial image captured with the mirror rotor positioned at the initial setting angle of 0° as shown in FIG. 1 is a schematic diagram showing how an actual photographing angle is calculated for photographed images at each set angle subsequent to the initial photographed image. FIG. 2 is a schematic flowchart showing the flow of processing of an image inspection method executed using the image inspection device shown in FIG. 1. FIG. 3 is a schematic diagram showing how the image inspection device shown in FIG. 1 is used in a part assembly operation for a connector terminal of a terminal-attached electric wire.

[0011] An embodiment of an image inspection device and an image inspection method will be described below.

[0012] FIG. 1 is a perspective view showing an image inspection device according to an embodiment.

[0013] The image inspection device 1 of this embodiment is a device that takes a terminal-attached electric wire W1 shown in Figure 2 and subsequent figures as a workpiece to be inspected, photographs the electric wire from multiple angles around the wire, and performs an appearance inspection, etc. based on the photographed images. This image inspection device 1 first includes a device frame 11, a mirror rotating body 12, a photographing unit 13, a driving unit 14, and a processing unit 15.

[0014] The device frame 11 is a frame portion that supports the mirror rotor 12, the imaging unit 13, and the drive unit 14, and includes a base portion 111, a mirror rotation holder 112, and an imaging holder 113. The base portion 111 is a rectangular flat plate, and the mirror rotation holder 112 and the imaging holder 113 are installed on its upper surface in the longitudinal direction D11, arranged in this order from the workpiece side. The mirror rotation holder 112 is a rectangular flat plate that is erected on the upper surface of the base portion 111 with its long side extending in the erection direction D12. The mirror rotor 12 and the motor 141 of the drive unit 14 are held on the workpiece side of the front and back surfaces of the mirror rotation holder 112. Furthermore, a rotation transmission mechanism 142 of the drive unit 14 is held on the opposite surface of the mirror rotation holder 112. The imaging holding part 113 is a part that holds the imaging part 13 at an imaging position P11, which is on the opposite side of the mirror rotating body 12 across the mirror rotation holding part 112. The imaging holding part 113 includes a rectangular flat plate part 113a that is fixed to the base part 111 along the longitudinal direction D11, and a pair of holding legs 113b that are erected at both ends of the plate part 113a and that hold the imaging part 13.

[0015] The mirror rotating body 12 has one or more mirrors rotatably mounted around a predetermined axis X11 along the longitudinal direction D11 of the base portion 111, and is a component that reflects subject light from a workpiece placed as an inspection target on the axis X11 and guides it to an imaging position P11. As described above, the mirror rotating body 12 is rotatably held on the workpiece-side surface of the mirror rotation holding part 112. This mirror rotating body 12 will be described in detail later with reference to a separate drawing.

[0016] The photographing unit 13 is installed at the photographing position P11, and is a part that receives subject light from the workpiece and photographs the workpiece, and is equipped with a camera 131 and a photographing lens 132. The camera 131 is held by the holding leg 113b on the side of the photographing holding unit 113 that is farther from the mirror rotation holding unit 112 and is the part that photographs. The photographing lens 132 has a roughly cylindrical appearance, and one end side is held by the camera 131, and the middle part is held by the holding leg 113b on the mirror rotation holding unit 112 side of the photographing holding unit 113. This photographing lens 132 is a part that collects subject light from the mirror rotating body 12 and sends it to the camera 131.

[0017] The drive unit 14 is a component that drives the mirror rotor 12 to rotate around the axis X11, which serves as the center of rotation, and includes a motor 141 and a rotation transmission mechanism 142. The motor 141 is a servo motor whose rotation can be controlled and is held above the mirror rotor 12 on the workpiece side of the mirror rotation holder 112. The rotation transmission mechanism 142 includes a small pulley 142a, a large pulley 142b, and a transmission belt 142c. The small pulley 142a is a pulley component that passes through the mirror rotation holder 112 and is connected to the rotation shaft of the motor 141. The large pulley 142b is a pulley component that is rotatable around the axis X11 of the mirror rotor 12, passes through the mirror rotation holder 112 and is connected to the mirror rotor 12, and has a larger diameter than the small pulley 142a. The transmission belt 142c is a belt component that connects the small pulley 142a and the large pulley 142b and transmits the rotation of the small pulley 142a to the large pulley 142b.

[0018] The processing unit 15 is a control part that is connected to the illumination unit 121, the imaging unit 13, and the drive unit 14 (to be described later) in the mirror rotating body 12 to control their operation, and also performs various processes based on the image captured by the imaging unit 13. The processing unit 15 includes an imaging processing unit 151 and an imaging angle acquisition unit 152. The imaging processing unit 151 and the imaging angle acquisition unit 152 will be described in detail later with reference to separate drawings.

[0019] Next, the mirror rotating body 12 will be described in detail.

[0020] FIG. 2 is a perspective view of the mirror rotor shown in FIG. 1 as seen from the workpiece side, and FIG. 3 is a plan view showing the mirror rotor shown in FIG. 2 as it rotates around an axis serving as the center of rotation, as viewed from the direction of arrow V11 in FIG. 2. FIG. 4 is a cross-sectional view taken along line V12-V12 in FIG. 2, showing how subject light from the workpiece is directed toward the imaging unit in the mirror rotor shown in FIG. 2. Note that FIG. 3 shows the circular connecting plate 142b-1 of the large pulley 142b, which is not shown in FIG. 2, behind the mirror rotor 12. FIG. 4 also shows the mirror rotation holder 112, the large pulley 142b including the circular connecting plate 142b-1, and a portion of the imaging lens 132 in the imaging unit 13, all of which are shown in FIG. 1, along with the mirror rotor 12.

[0021] First, the terminal-attached electric wire W1 as the work in this embodiment is formed by crimping and connecting female connector terminals W13 to the ends of two electric wires W12 exposed in an untwisted state at the end of a twisted pair electric wire W11. The mirror rotating body 12 is provided with a rectangular work arrangement space 12a surrounding an axis X11 serving as the center of rotation of the mirror rotating body 12. The terminal-attached electric wire W1 is arranged on the axis X11 with its electric wire axis aligned along the axis X11 so that the electric wire ends crimped and connected to the connector terminals W13 fit within the work arrangement space 12a.

[0022] The mirror rotor 12 is provided with an illumination unit 121 that irradiates illumination light L11 (FIGS. 3 and 4) toward the interior of the work placement space 12a from one of four inner surfaces surrounding the axis X11 in the work placement space 12a. The mirror rotor 12 is also provided with a plurality of mirrors rotatable about the axis X11, including a half-mirror prism 122 and a pair of mirror prisms 123. The half-mirror prism 122 is a rectangular block-shaped prism component positioned between the illumination unit 121 and the work placement space 12a, with one of its outer surfaces facing the inner surface of the work placement space 12a. A half mirror is formed on the inner diagonal surface of the half-mirror prism 122, which transmits the illumination light L11 from the illumination unit 121 into the work placement space 12a. Furthermore, the half-mirror prism 122 reflects reflected light L12, which is the illumination light L11 reflected by the terminal-attached electric wire W1 serving as the work, and guides it to the imaging side as subject light. The illumination unit 121 is connected to the processing unit 15 via an illumination cable 121a (FIG. 1).

[0023] Reflected light L12 as subject light reflected by the half mirror prism 122 is reflected by one mirror prism 123 toward the axis X11, and is then reflected by another mirror prism 123 so as to travel along the axis X11 toward the photographing side. The reflected light L12 reflected by the last mirror prism 123 passes through the through-hole 142b-2 of the large pulley 142b including the circular connecting plate 142b-1, enters the photographing lens 132 of the photographing unit 13, and is collected toward the camera 131.

[0024] The drive unit 14 shown in FIG. 1 drives the mirror rotor 12 described above to rotate around the axis X11 on which the terminal-attached electric wire W1 as the workpiece is disposed, in a clockwise rotation direction D13 as viewed from the workpiece side as shown in FIG. 3 . At this time, the drive unit 14 sends a signal representing the motor rotation angle of the motor 141 to the processing unit 15. The photography processing unit 151 in the processing unit 15 causes the drive unit 14 to rotate the mirror rotor 12 and causes the photography unit 13 to photograph the terminal-attached electric wire W1 when the mirror rotor 12 is positioned at a preset angle. The photography processing unit 151 monitors the rotation angle θ11 of the mirror rotor 12 based on the motor rotation angle represented by the signal from the drive unit 14. The rotation angle θ11 of the mirror rotor 12 here is the angle formed by a mirror reference axis X13 along the irradiation direction D14 of the illumination light L11 at the mirror rotor 12, relative to the device reference axis X12 shown in FIG. 3 . The apparatus reference axis X12 is an axis in the vertical direction that intersects with the axis X11 along the erection direction D12 of the mirror rotation holder 112 in the apparatus frame 11.

[0025] The photographing processing unit 151 causes the photographing unit 13 to photograph when the rotation angle θ11 of the mirror rotating body 12 being monitored reaches a preset angle. In this embodiment, eight angles are set as the preset angle from 0° to 315° in increments of 45°.

[0026] FIG. 5 is a schematic diagram showing images taken at four set angles from 0° to 135° lined up, and FIG. 6 is a schematic diagram showing images taken at four set angles from 180° to 315° lined up.

[0027] As shown in FIGS. 5 and 6 , the captured image G11 obtained by the image capture processing performed by the image capture processing unit 151 is a multi-plane captured image of the terminal-attached electric wire W1 as a workpiece viewed from eight angular directions around the axis X11. Here, the rotation angle θ11 of the mirror rotator 12 monitored by the image capture processing unit 151 is obtained by converting the motor rotation angle of the motor 141 recognized by the drive unit 14. The image capture processing unit 151 then captures images when the converted rotation angle θ11 of the mirror rotator 12 reaches one of the eight set angles, and obtains eight captured images using each set angle as a temporary capture angle. At this time, the following angular deviations may occur between the set angle of each captured image and the actual capture angle. First, there is a possibility that rotational deviation of the mirror rotator 12 in the drive unit 14 is included. Furthermore, even if this rotational deviation is zero, there is a possibility that angular deviation due to the prism arrangement of the mirror rotator 12 or the like is included between the rotation angle θ11 of the mirror rotator 12 and the capture angle. A combination of these factors may result in an angular misalignment between the set angle and the actual shooting angle. In this embodiment, the processing unit is provided with a shooting angle acquisition unit 152 that corrects such an angular misalignment and acquires the actual shooting angle of the captured image G11 that corresponds to the set angle. The following alignment unit 16 ( FIG. 2 ) provided on the mirror rotating body 12 is used to acquire the actual shooting angle in this shooting angle acquisition unit 152.

[0028] FIG. 7 is a diagram showing an alignment unit used to acquire the actual imaging angle. In FIG. 7, the alignment unit 16 is shown together with a bottom plate member 124 having a rectangular bottom surface 124a that faces the transmission surface of the irradiated light L11 among the inner surfaces of the workpiece placement space 12a of the mirror rotor 12, and the terminal-attached electric wire W1 as the workpiece. A pair of alignment units 16 are provided so as to be held by a pair of alignment holders 125 erected on a pair of side edges along the axis X11 of the bottom surface 124a of the bottom plate member 124. This pair of alignment units 16 rotates together with the mirror rotor 12 around the axis X11 and is photographed together with the terminal-attached electric wire W1 as shown in FIGS. 5 and 6 . This alignment unit 16 serves as a reference for positioning the workpiece in the photographed image G11. In this embodiment, the alignment unit 16 as a positioning reference is used as follows to acquire the actual imaging angle in the imaging angle acquisition unit 152.

[0029] The imaging angle acquisition unit 152 first calculates the angular deviation between the actual initial imaging angle and the initial imaging angle for an initial imaging image corresponding to a predetermined initial setting angle, based on the alignment portion 16 that appears in the initial imaging image. In this embodiment, the imaging angle acquisition unit 152 calculates the angular deviation between the actual initial imaging angle and the ... G11 that is captured at a setting angle of 0° shown in FIG. 5 as the initial setting angle and the initial setting image. Thereafter, the imaging angle acquisition unit 152 corrects the setting angle by the angular deviation to acquire the actual imaging angle.

[0030] Fig. 8 is a diagram showing how the mirror rotator is set to an initial setting angle of 0° for calculating the angular deviation in the image inspection device shown in Fig. 1. Fig. 8 shows a perspective view of the image inspection device 1 as seen from the mirror rotator 12 side.

[0031] First, in this embodiment, the image inspection device 1 includes a removable angle adjustment jig 17 that positions the mirror rotor 12 at an initial setting angle of 0° around the axis X11 during installation. This angle adjustment jig 17 is a round rod-shaped member that is inserted from the side edge of the mirror rotation holder 112. A jig recess 142b-1a is formed on the periphery of the circular connecting plate 142b-1 of the large pulley 142b at a position that faces the insertion side of the angle adjustment jig 17 when the connected mirror rotor 12 is positioned at the initial setting angle of 0°. Then, by inserting the tip of the angle adjustment jig 17 into this jig recess 142b-1a, the mirror rotor 12 is positioned at the initial setting angle of 0° via the circular connecting plate 142b-1. In this state, the imaging unit 13 performs imaging to obtain an initial captured image, and the imaging angle acquisition unit 152 calculates the angle misalignment using this initial captured image.

[0032] Fig. 9 is a schematic diagram showing how the angular deviation from the initial setting angle is calculated based on an initial captured image taken with the mirror rotor positioned at the initial setting angle of 0° as shown in Fig. 8. In Fig. 9, the initial captured image G110 is shown with the peripheral portion of the alignment section 16 cut out.

[0033] As described above, the alignment portions 16 are provided as a pair, sandwiching the axis X11 between them and the terminal-attached electric wire W1 as the workpiece. They are captured in this state in the captured image G11, including the initial captured image G110. The capture angle acquisition unit 152 calculates an initial angle deviation θ12, which is the angular deviation between the initial setting angle of 0° and the actual initial capture angle, based on the pair of alignment portions 16 captured in the initial captured image G110. First, the capture angle acquisition unit 152 determines an alignment line 161 connecting the pair of alignment portions 16 in the initial captured image G110. Here, the alignment portions 16 have a round pin shape that appears as a circular image in the captured image G11 (initial captured image G110). The capture angle acquisition unit 152 determines the alignment line 161 as a line connecting the centers 162 of the alignment portions 16 captured as a pair of circular images in the initial captured image G110. At this time, the initial setting angle is 0°, and in the initial captured image G110, a line that crosses the image horizontally is the initial setting line G101 that corresponds to the initial setting angle. The capturing angle acquisition unit 152 then calculates the angle that the alignment line 161 makes with respect to the 0° initial setting line G101 as the initial angle deviation θ12 between the actual initial capturing angle and the initial setting angle. In this embodiment, since the initial setting angle is 0°, this initial angle deviation θ12 is the actual initial capturing angle itself. This initial angle deviation θ12 does not include rotational deviation in the drive unit 14, but only includes angle deviation due to the prism arrangement on the mirror rotor 12, etc.

[0034] Once the initial captured image G110 has been captured and the initial angle deviation θ12 has been calculated, the angle adjustment jig 17 is removed, allowing the mirror rotor 12 to rotate. Thereafter, under the processing of the image processing unit 151, seven captured images G11 are captured at set angles of 45° to 315° in 45° increments. Then, the actual capturing angles of the captured images G11 at each set angle are calculated as follows:

[0035] 10 is a schematic diagram showing how the actual photographing angles are calculated for photographed images at each set angle following the initial photographed image. In this figure, a photographed image G11 photographed at a set angle of 45° is used as a representative example, and the photographed image G11 is shown with the peripheral portion of the alignment portion 16 cut out.

[0036] The set angle θ13 set for the rotation angle θ11 of the mirror rotor 12 shown in FIG. 3 is the angle between the horizontal initial setting line G101 shown in FIG. 9 and the set line G102 corresponding to the set angle θ13 in the captured image G11. In the example of FIG. 10, this set angle θ13 is 45°. The angular deviation θ14 between the actual shooting angle and the set angle θ13 is the angle between the alignment line 161 connecting the centers 162 of the alignment unit 16 and the set line G102. The angular deviation θ14 at this time may include not only the initial angular deviation θ12 shown in FIG. 9 but also a rotational deviation in the drive unit 14. However, in the drive unit 14 of this embodiment, which uses a servo motor as the motor 141, the angular deviation θ14 is negligibly small compared to the initial angular deviation θ12, and can be considered to be approximately equal to the initial angular deviation θ12. Therefore, in this embodiment, the actual shooting angle for each captured image G11 is calculated by correcting the set angle θ13 with the initial angle deviation θ12.

[0037] In this way, eight photographed images G11 including the initial photographed image G110 are acquired as a set with the actual photographing angles as a result of multi-plane photographing of the terminal-attached electric wire W1 as the workpiece. Then, the processing unit 15 performs inspection processing such as an appearance inspection based on these photographed images G11.

[0038] Next, an outline of an image inspection method executed using the image inspection device 1 described above will be described, although some of the description will overlap with the above.

[0039] FIG. 11 is a schematic flowchart showing the flow of processing of an image inspection method executed using the image inspection apparatus shown in FIG.

[0040] First, a work placement step (S11) is performed in which a terminal-attached electric wire W1 as a work is placed on the axis X11 in the work placement space 12a of the mirror rotor 12 of the image inspection device 1. Next, an initial photographing processing step (S12) is performed in which an initial photographed image G110 is photographed under the processing of the photographing processing unit 151 with the mirror rotor 12 positioned at an initial setting angle of 0° by the angle adjustment jig 17. After that, an initial angle deviation acquisition step (S13) is performed in the photographing angle acquisition unit 152 in which an initial angle deviation θ12 is calculated based on the alignment unit 16 of the photographed initial photographed image G110. The initial angle deviation θ12 at this time is used as the actual initial photographing angle for the initial photographed image G110.

[0041] Next, the angle adjustment jig 17 is removed, and an additional photographing process step (S14) is performed under the control of the photographing processing unit 151, in which photographed images G11 are captured at multiple set angles θ13 starting from 45°. In the additional photographing process step (S14), the photographing processing unit 151 causes the driving unit 14 to rotate the mirror rotating body 12, and causes the photographing unit 13 to photograph the terminal-attached electric wire W1 when the mirror rotating body 12 is positioned at the preset set angle θ13. Next, the photographing angle acquisition unit 152 performs a photographing angle acquisition step (S15) in which the actual photographing angle of the photographed image G11 corresponding to the set angle θ13 is acquired based on the alignment unit 16 shown in the photographed image G11. Specifically, in this photographing angle acquisition step (S15), the set angle θ13 of each photographed image G11 is corrected by the initial angle deviation θ12 acquired based on the alignment unit 16 in the initial angle deviation acquisition step (S13), thereby acquiring the actual photographing angle. Finally, an inspection processing step (S16) is executed in which the processing unit 15 performs processing such as visual inspection of the terminal-attached electric wire W1 based on multiple captured images G11 including the initial captured image G110 obtained by the processing up to this point.

[0042] The image inspection device 1 of this embodiment is used for the following part mounting work on the connector terminal W13 of the terminal-attached electric wire W1.

[0043] FIG. 12 is a schematic diagram showing how the image inspection device shown in FIG. 1 is used in a part assembly operation for a connector terminal of a terminal-attached electric wire.

[0044] Some connector terminals W13 of the terminal-attached electric wire W1 have a shielding plate W14 attached to them after the terminal is crimped. As an assembly condition for this shielding plate W14, a restriction may be imposed that the rotational orientation of the connector terminal W13 about the axis X11 must be within ±5° of an ideal reference orientation. The reference orientation here refers to an orientation in which, when the mounting surface of the shielding plate W14 of the connector terminal W13 is defined as a work reference plane W131, this work reference plane W131 faces directly upward, toward the assembly side of the shielding plate W14. The image inspection device 1 of this embodiment is used to adjust the rotational orientation of the connector terminal W13 when such a restriction is imposed.

[0045] 12 , first, a connector terminal W13 is crimped to produce a terminal-attached electric wire W1 (step S21). The terminal-attached electric wire W1 after the terminal crimping is placed as a workpiece inside the work placement space 12a of the mirror rotator 12 in the image inspection device 1 (step S22). In step S22, the above-described multi-plane photographing and a terminal appearance inspection using a plurality of photographed images G11 including the initial photographed image G110 are subsequently performed, and the following terminal angle measurement is also performed. First, the terminal-attached electric wire W1 is placed inside the work placement space 12a so that, when the mirror rotator 12 is at an initial setting angle of 0°, the workpiece reference plane W131 of the connector terminal W13 extends along the axis X11 and faces the illumination unit 121.

[0046] In this state, the photographing processing unit 151 performs the following front photographing control on the drive unit 14 and the photographing unit 13. In this front photographing control, photographed images are captured while changing the set angle around 0°. Furthermore, the photographing processing unit 151 calculates the width dimension of the intersection width d11 of the workpiece reference surface W131 with the axis X11 at each photographing time. The drive unit 14 and the photographing unit 13 are then controlled so that a photographed image capturing the workpiece reference surface W131 at the maximum width d12 around 0° is captured as the front photographed image of the connector terminal W13. The front photographed image captured at this time is an image captured when the mirror rotating body 12 is rotated to a position where the illumination unit 121 directly faces the workpiece reference surface W131 if the connector terminal W13 is tilted around the axis X11. As a result, the actual photographing angle when this front photographed image is captured can be considered the terminal front angle around the axis X11 of the connector terminal W13. In step S22, the imaging angle acquisition unit 152 executes a front angle acquisition process to acquire the actual imaging angle of the front image as the terminal front angle. The actual imaging angle is acquired by correcting the set angle of the front image using the initial angle deviation described above. The terminal front angle acquired in this manner represents the rotational orientation of the connector terminal W13 about the axis X11 when viewed from the direction of the axis X11.

[0047] The terminal front angle acquired by the image inspection device 1 in this manner is sent to a terminal holding mechanism (not shown). The terminal holding mechanism, which has received the terminal front angle, uses the terminal front angle to perform a terminal angle correction process so that the rotational posture of the connector terminal W13 about the axis X11 falls within ±5° of the ideal reference posture (step S23). Finally, the shielding plate W14 is assembled toward the workpiece reference plane W131 of the connector terminal W13 that has undergone the terminal angle correction process (step S24).

[0048] The image inspection device 1 and image inspection method of the embodiment described above can provide the following effects. That is, according to this embodiment, the alignment portion 16, which is photographed together with the electric wire with terminals W1 in the photographed image G11, is arranged to rotate together with the mirror rotating body 12. Therefore, the alignment portion 16 itself photographed in the photographed image G11 contains image information related to the rotation angle, i.e., the photographing angle G11. Then, according to this embodiment, the photographing angle acquisition unit 152 performs processing based on the alignment portion 16 in the photographed image G11, thereby making it possible to determine the tilt of the electric wire with terminals W1 itself and the actual photographing angle at which it can be separated.

[0049] In this embodiment, the imaging angle acquisition unit 152 calculates an initial angle deviation θ12 between the actual initial imaging angle and the initial setting angle (0°) based on the alignment portion 16 shown in the initial imaging image G110. Then, the imaging angle acquisition unit 152 acquires the actual imaging angle by performing correction using this initial angle deviation θ12. According to this configuration, the actual imaging angle can be acquired with reduced processing load by performing correction using the initial angle deviation θ12.

[0050] In this embodiment, the photography processing unit 151 sets the set angle using, as an initial setting angle, the drive angle of the drive unit 14 when the mirror rotor 12 is positioned by the angle adjustment jig 17. According to this configuration, by positioning the mirror rotor 12 using the angle adjustment jig 17, the initial setting angle, that is, the set angle, can be stably set.

[0051] Furthermore, in this embodiment, the photographing angle acquisition unit 152 calculates the angle that an alignment line 161 connecting a pair of alignment portions 16 in the initial photographed image G110 makes with respect to an initial setting line G101 corresponding to the initial setting angle (0°) as the initial angle deviation θ12. With this configuration, the alignment line 161 for calculating the initial angle deviation θ12 can be obtained based on the pair of alignment portions 16 in the photographed image G11, and therefore the initial angle deviation θ12 can be calculated effectively.

[0052] Furthermore, in this embodiment, the imaging angle acquisition unit 152 obtains, as the alignment line 161, a line connecting the centers 162 of the pair of circular images that are images of the alignment line 161 in the initial captured image G110. With this configuration, the alignment line 161 is obtained based on the centers 162 of the pair of circular images, which are points that can be obtained accurately, and therefore the accuracy of the initial angle deviation θ12 and, ultimately, the actual imaging angle can be improved.

[0053] In this embodiment, the photographing processing unit 151 also performs front photographing control, which controls the drive unit 14 and the photographing unit so that the photographed image G11, in which the workpiece reference surface W131 is captured at the maximum width d12, is captured as a front photographed image. The photographing angle acquisition unit 152 also performs front angle acquisition processing, which acquires the actual photographing angle of the front photographed image as the terminal front angle about the axis X11 of the connector terminal W13 of the terminal-attached electric wire W1 as the work. With this configuration, the terminal front angle of the connector terminal W13 can be effectively acquired by using the actual photographing angle of the front photographed image in which the workpiece reference surface W131 is captured at the maximum width d12.

[0054] The above-described embodiments merely show typical forms of the image inspection device and image inspection method. The image inspection device and image inspection method are not limited to these, and can be implemented in various modifications.

[0055] For example, in the above-described embodiment, an image inspection device 1 is exemplified as an example of an image inspection device, which photographs a terminal-attached electric wire W1 in which a connector terminal W13 is crimped to the end of a twisted pair electric wire W11 as a workpiece and performs various inspections. However, the image inspection device is not limited to this, and may photograph and inspect a terminal-attached electric wire in which a connector terminal is crimped to the end of a single electric wire, other electric wires, or any member other than an electric wire as a workpiece.

[0056] Furthermore, in the above-described embodiment, as an example of an image inspection device, an image inspection device 1 is exemplified that performs multi-plane imaging based on subject light from the rotating mirror rotor 12 while rotating the mirror rotor 12. However, the image inspection device is not limited to this, and may perform multi-plane imaging by stopping the mirror rotor at a plurality of set angles and performing imaging.

[0057] In the above-described embodiment, an image inspection device 1 that performs multi-plane imaging by capturing images at eight set angles in 45° increments is exemplified as an example of an image inspection device. However, the image inspection device is not limited to this, and may perform multi-plane imaging at an angle interval other than 45° and at a number other than eight, or may perform multi-plane imaging while changing the angle interval itself. Alternatively, the image inspection device may be positioned at one set angle by rotating a mirror rotor, and perform single-plane imaging at only that one set angle.

[0058] Furthermore, in the above-described embodiment, as an example of a mirror rotator, a mirror rotator 12 provided with one half mirror prism 122 and a pair of mirror prisms 123 is given. However, the mirror rotator is not limited to this, and the number and shape of the mirrors are not limited to a specific number as long as the mirror rotator has one or more mirrors.

[0059] In the above-described embodiment, the imaging angle acquisition unit 152 is exemplified as an example of an imaging angle acquisition unit. The imaging angle acquisition unit 152 calculates the initial angle deviation θ12 based on the alignment unit 16 and acquires the actual imaging angle by correcting other set angles using the initial angle deviation θ12. However, the imaging angle acquisition unit is not limited to this. The imaging angle acquisition unit may calculate the angle deviation for each captured image individually based on the alignment unit 16, and correct the set angle using each of these individual deviations. However, as described above, the processing load can be reduced by limiting the calculation of the angle deviation based on the alignment unit 16 to the initial angle deviation θ12 and using this initial angle deviation θ12 to correct other set angles. In this embodiment, 0° is exemplified as an example of the initial setting angle. However, the initial setting angle is not limited to this, and any angle other than 0° can be used.

[0060] In the above-described embodiment, the image inspection device 1 is exemplified as an example of an image inspection device, which is equipped with an angle adjustment jig 17 that positions the mirror rotor 12 at an initial setting angle of 0°. However, the image inspection device is not limited to this, and no jig may be used for setting the initial setting angle. However, as described above, by using the angle adjustment jig 17, the initial setting angle, i.e., the set angle, can be stably set.

[0061] Furthermore, in the above-described embodiment, the imaging angle acquisition unit 152 is exemplified as an example of an imaging angle acquisition unit, which calculates the angle that the alignment line 161 connecting the pair of alignment units 16 makes with respect to the setting line G101 as the angular misalignment. However, the imaging angle acquisition unit is not limited to this, and any specific acquisition method is not important as long as it acquires the actual imaging angle based on the alignment units shown in the captured image. However, as described above, by calculating the angle that the alignment line 161 makes with respect to the setting line G101 as the angular misalignment, the angular misalignment can be effectively calculated.

[0062] Furthermore, in the above-described embodiment, as an example of an image inspection device, an image inspection device 1 is exemplified, which is provided with an alignment unit 16 that appears as a circular image in the captured image, and in which the imaging angle acquisition unit 152 determines an alignment line 161 that connects the centers 162 of a pair of circular images in the image. However, the image inspection device is not limited to this, and the image shape of the alignment unit when it appears in the image may be any shape, and the specific method of determining the alignment line is not limited to this. However, as described above, by the imaging angle acquisition unit 152 determining the alignment line 161 that connects the centers 162 of the circular images of the alignment unit 16, the accuracy of the actual imaging angle can be improved.

[0063] Furthermore, in the above-described embodiment, an example of an image inspection device is an image inspection device 1 that is used for assembling the shielding plate W14 to the connector terminal W13, in which the image capture processing unit 151 performs front image capture control and the image capture angle acquisition unit 152 performs front angle acquisition processing. However, the image inspection device is not limited to this, and may be one that is not used for assembling the shielding plate W14, etc., and that only captures images of multiple or single sides of a workpiece and performs an appearance inspection. However, as described above, the above-described front image capture control and front angle acquisition processing make it possible to effectively acquire the terminal front angle of the connector terminal W13 that is suitable for assembling the shielding plate W14 to the connector terminal W13.

[0064] 1 Image inspection device 11 Device frame 12 Mirror rotating body 12a Work placement space 13 Photography unit 14 Drive unit 15 Processing unit 16 Alignment unit 17 Angle alignment jig 111 Base part 112 Mirror rotation holding unit 113 Photography holding unit 113a Plate part 113b Holding leg 121 Lighting unit 121a Lighting cable 122 Half mirror prism 123 Mirror prism 124 Bottom plate member 124a Bottom surface 125 Alignment holding unit 131 Camera 132 Photography lens 141 Motor 142 Rotation transmission mechanism 142a Small pulley 142b Large pulley 142b-1 Circular connecting plate 142b-1a Jig recess 142b-2 Through hole 142c Transmission belt 151 Photography processing unit 152 Photography angle acquisition unit 161 Alignment line 162 Center d11 Intersection width d12 Maximum width D11 Longitudinal direction D12 Vertical direction D13 Rotation direction D14 Irradiation direction G11 Photography image G110 Initial photography image G101 Initial setting line G102 Setting line L11 Illumination light L12 Reflected light P11 Photography position S11 Work placement process S12 Initial photography processing process S13 Initial angle deviation acquisition process S14 Other photography processing process S15 Photography angle acquisition process S16 Inspection processing process W1 Terminal-attached wire W11 Twisted pair wire W12 Wire W13 Connector terminal W14 Shielding plate W131 Work reference surface X11 Axis line X12 Device reference axis X13 Mirror reference axis θ11 Rotation angle θ12 Initial angle deviation θ13 Set angle θ14 Angle deviation

Claims

1. An image inspection device comprising: a mirror rotor having one or more mirrors rotatable about a predetermined axis, which reflects subject light from a workpiece placed on the axis as an inspection target and guides it to a photographing position; an imaging unit which is installed at the photographing position and receives the subject light to photograph the workpiece; an alignment unit which is installed on the mirror rotor so as to rotate together with the mirror rotor around the axis and be photographed together with the workpiece, and which serves as a reference for positioning the workpiece; a drive unit which drives the mirror rotor to rotate around the axis; an imaging processing unit which drives the drive unit to rotate the mirror rotor and causes the imaging unit to photograph the workpiece when the mirror rotor is positioned at a predetermined set angle; and an imaging angle acquisition unit which acquires the actual imaging angle of the photographed image corresponding to the set angle based on the alignment unit which appears in the photographed image.

2. The image inspection device described in claim 1, characterized in that the shooting angle acquisition unit calculates the angular deviation between the actual initial shooting angle and the initial setting angle for an initial shooting image corresponding to a predetermined initial setting angle based on the alignment part that appears in the initial shooting image, and acquires the actual shooting angle by correcting the set angle with the angular deviation.

3. The image inspection device described in claim 2, further comprising a removable angle adjustment jig that positions the mirror rotor at a predetermined initial angle around the axis when installed, and wherein the photography processing unit sets the set angle using the drive angle of the drive unit when the mirror rotor is positioned by the angle adjustment jig as the initial setting angle.

4. The image inspection device described in claim 1, characterized in that the alignment units are provided in pairs with the axis line sandwiched between them, and the shooting angle acquisition unit calculates the angle that an alignment line connecting the pair of alignment units in the captured image makes with a setting line corresponding to the setting angle as the angular deviation between the actual shooting angle and the setting angle, and acquires the actual shooting angle by correcting the setting angle with the angular deviation.

5. The image inspection device described in claim 4, characterized in that the alignment unit has a shape that appears as a circular image in the captured image, and the shooting angle acquisition unit obtains the alignment line as a line connecting the centers of a pair of the circular images in the captured image.

6. The image inspection device according to claim 1, wherein the workpiece is placed on a predetermined workpiece reference surface so that the workpiece reference surface extends along the axis, the photography processing unit takes the photographed images while changing the set angle, calculates the width dimension of the intersection width of the workpiece reference surface with the axis in the photographed image at each set angle, and also performs front photography control to control the drive unit and the photography unit so that the photographed image in which the workpiece reference surface is captured at its widest width is taken as a front photographed image of the workpiece, and the photography angle acquisition unit also performs front angle acquisition processing to acquire the actual photography angle for the front photographed image as a front angle around the axis of the workpiece when the workpiece is viewed from the direction of the axis.

7. An image inspection method comprising: a workpiece placement step of placing the workpiece on the axis of the image inspection device described in any one of claims 1 to 6; an image processing step of driving the mirror rotor to rotate with the drive unit and causing the image capture unit to capture an image of the workpiece when the mirror rotor is positioned at a preset angle; and an image angle acquisition step of acquiring the actual image capture angle of the captured image corresponding to the set angle based on the alignment unit that appears in the captured image.

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